In the prior art, there exist various data building structures for housing a multiplicity of racks, each of which comprising storage space for computer hardware. For instance, a conventional data centre building according to the prior art is sketched in FIG. 1. It comprises a false floor for a computer infrastructure, which is typically housed in 19″ rack enclosures. The cooling is accomplished by cold air, which is pumped into the false floors having holes at the appropriate locations in front of the racks. In this way cold air is supplied at the air intakes of the computer racks.
Referring to FIG. 1, the floor 106 carries the false floor, assembled from vertical steel bars 107, carrying the floor tiles 104, 105, which in turn carry the computer infrastructure, for instance 19″ racks 102. These racks 102 typically host 19″ rack mounted computer infrastructure 101, which is horizontally mounted and acquires air at the front-side of the rack and produces warm air at the back side. In order to cool the computers, the false floor tiles have appropriate air holes 104, such that cold air 110 can be ingested into the racks 102.
In the prior art also an encapsulated cold air aisle 103 is provided in order to avoid, that hot air 109 short circuits the flow of cold air. By means of such an encapsulation, the provided cold air 110, 111 may only leave the aisle 103 via the computers' air intake and correspondingly there is no other way for the heated air to enter this space.
This design is somehow disadvantageous, because the single racks 102 have to be designed as closed racks. Further, the air flow through respective racks 102 has to be surveyed and controlled in order to avoid pumping unnecessary amounts of cold air from the cold aisle. There exist various concepts, providing a regulation of the air flow into the cold isle 103, such that the fans providing the air flow 108 operate at the lowest possible power. The hot air 109 generated at the back of the rack 102 is fed back to not explicitly illustrated heat exchangers being located somewhere else in the data centre building. The heated air is either cooled down again or fresh air is used in order to provide a stream of cold air 108.
This architecture has various disadvantages. First of all, the comparably small heat capacity of air requires rather high temperature differences between the cold air and the heated air. Further, a high air flow rate with corresponding large losses due to air pumping is also required. Reasonable limits of the air flow rate and the air temperature limit the overall size of the data centre building. Further, an air cooling system typically requires 40% of cooling overheat. Moreover, the false floor architecture is quite expensive and wastes volume inside the building.
Document WO 02/052107 A2 further discloses a data centre building comprising a ground floor and spaced lower and upper mezzanine floors between the ground floor and a roof. Each of the mezzanine floors has an open decking for allowing the passage of ambient air, whereby a forced circulation of ambient air is suggested in order to maintain the data centre at acceptable operating temperatures. Even though this described building avoids the use of false or raised flooring by making use of industrial or warehouse space with mezzanine floor constructions, the heat dissipation mechanism is still not optimal, because a vast amount of cooling air has to be forced through the entire building structure, which is difficult to control and which is rather inefficient.
Also here, the overall building size is limited, because for an efficient cooling, the entire inner volume of the building has to be sufficiently supplied with ambient air flow. Further, this architecture does not support multiple floors with large heating sources like computing racks, because the air temperature would rise more and more towards the upper floors. The referred prior art only supports one floor with rather low power density, for instance implementing network equipment and one floor with computer infrastructure.